The use of genetically engineered microbes can offer enormous potential benefits. Genetically modified organisms can be used industrially to produce a wide range of fuels and chemicals using CO2 as a carbon source, water as an electron source, and sunlight as an energy source. Some caution is warranted, however, because information about the ecology and evolution of transgenic microbes in the wild is limited, Microbes occur in extremely large populations with short generation times, so they adapt quickly to adverse conditions, Bacteria also can transfer DNA into unrelated microbes, and the long-term ecological consequences of that transfer are unclear (Bushman, 2002). The con sequences of releasing transgenic microbes into the environment have not been evaluated adequately. It is desirable to take precautions to prevent robust viability of a genetically modified organism outside of a controlled growth environment, e.g., to prevent or mitigate untoward environmental consequences following inadvertent release of a genetically modified organism into the wild.